In the first U.S. study to evaluate the specific relationships between measured traffic pollutants from nearby roads and respiratory symptoms of youngsters, investigators have shown that there were modest but significant increases in the odds for either bronchitis or physician-diagnosed asthma among children who had lived at least 1 year in neighborhoods with higher concentrations of traffic pollutants. During the study, researchers analyzed 1,109 questionnaires returned from students in 64 participating classrooms in 10 schools involved in the East Bay Children's Respiratory Health Study. They obtained information on bronchitis symptoms and physician-confirmed asthma for the preceding 12 months, using English and Spanish questionnaires. In addition, they measured concentrations of traffic pollutants (particulate matter, black carbon, and nitrogen oxides) at the 10 school sites for a number of weeks during the spring and fall months. As they studied the full sample, the authors said that associations were observed between both asthma in the past 12 months and the pollutants, especially nitrogen oxides and black carbon. They said that their findings were observed in a region that had relatively clean air, including low concentrations of ozone and particulate matter. Since most of the children walked to school, they assumed that traffic-related pollutants measured at the neighborhood school would be a good proxy for the children's overall exposure to the pollutants. The study appears in the first issue for September 2004 of the American Journal of Respiratory and Critical Care Medicine.
TUBERCULOSIS TREATMENT OUTCOMES COMPARED
When investigators compared tuberculosis (TB) patients who participated in directly observed therapy to patients with risk factors for non-adherence who performed self-administered therapy, they found that cure occurred in almost 98 percent of the patients treated by directly observed therapy as contrasted to a rate of slightly over 80 percent for the self-medicated patients. During their study, the researchers compared treatment outcomes among 372 patients. When risk factors for non-adherence were not considered, the 149 patients treated by directly observed therapy also had a significantly higher cure rate (97.8 percent) than did the 223 persons treated by self-administered therapy (88.6 percent). According to the authors, treatment of TB is challenging for both patients and providers. Directly observed therapy was defined as ingestion of anti-tuberculosis medications under the direct supervision of a health care worker. TB drugs need to be taken for a minimum of at least six months to show an effective outcome. In their study population, the patients treated by directly observed therapy had higher rates of HIV infection and drug-resistant TB, which was a reason for exclusion from this study. Both factors are known to be associated with poor response to treatment. In addition, the directly observed patients had high rates of homelessness, substance abuse with alcohol and other drugs, and a history of incarceration, all of which are thought to compromise treatment adherence. The authors said that 44 percent of patients who receive self-administered therapy had risk factors and should have been assigned to directly observed therapy instead. The researchers suggested an educational program for physicians who referred patients to help them to understand appropriate factors. The study was published in the first issue for September 2004 of the American Thoracic Society's peer-reviewed American Journal of Respiratory and Critical Care Medicine.
DIMINISHED INFANT LUNG FUNCTION ASSOCIATED WITH GREATER POSTNATAL WEIGHT GAIN
Based on study findings, British researchers believe that lower rates of fetal growth and higher rates of weight gain in early infancy are associated with impaired lung development. They analyzed size at birth and weight gain in early infancy in relationship to lung function in 131 normal term infants. Lung function was measured from 5 to 14 weeks after birth. Using standard criteria, seven percent of the infants were in less than the 10th percentile of birth weight for gestation. The authors said that their data suggested that restricted fetal growth is associated with particular impairment of lung and airway development. Moreover, they said that their data indicate that the reduced adult lung function of individuals of below average birth weight in part originates from impaired lung and airway development in the prenatal and immediate postnatal periods and not simply from increased susceptibility to respiratory illness after birth. They said that one explanation for their findings is that above average weight gain may serve to identify fetuses that had followed a rapid trajectory of prenatal growth which faltered in late pregnancy, impairing lung growth and development. Fetuses subject to such growth faltering in late gestation have increased postnatal weight gain unless they are exposed to severe and prolonged restriction in nutrient supply in utero. The research was published in the first issue for September 2004 of the American Thoracic Society's peer-reviewed American Journal of Respiratory and Critical Care Medicine.
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Journal
American Journal of Respiratory and Critical Care Medicine